Text messaging improves preoperative exercise in patients undergoing bariatric surgery.

BACKGROUND: To investigate whether a text message intervention improves adherence to preoperative exercise advice prior to laparoscopic sleeve gastrectomy (LSG). METHODS: A single-blinded parallel design 1:1 ratio randomized controlled trial was performed in patients undergoing LSG as a single-stage bariatric procedure for morbid obesity. The intervention group received preoperative daily text messages. The primary outcome was adherence to preoperative exercise advice as assessed by the number of participants partaking in ≥450 metabolic equivalent minutes (METmin-1 ) exercise activity per week preoperatively. RESULTS: Eighty-eight patients were included in the analysis with 44 allocated to each arm. Adherence and exercise activity increased significantly from baseline in the exposure group (EG) but not in the control group (CG). Adherence was significantly higher in the EG at the end of the intervention period compared to the CG. Despite increased exercise activity, there was no improvement in 6-min walk test or surgical recovery. CONCLUSION: A daily text message intervention improved adherence to preoperative exercise advice, but this did not correlate with improved surgical recovery.

The effect of oral simvastatin on fibrinolytic activity after colorectal surgery-a pilot study.

BACKGROUND: Studies conducted in animal models have shown that statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) reduce adhesion formation by upregulating fibrinolysis. The aim of this study was to determine the effect of orally administered statins on the promoters and inhibitors of the fibrinolytic pathway. METHODS: In a previously described double-blinded clinical trial, 144 patients undergoing elective colorectal resection, or reversal of Hartmann's procedure were randomized to receive 40 mg once daily oral simvastatin 3-7 d before surgery or placebo. For the purposes of the present study, peritoneal drain fluid was collected postoperatively from patients to measure active tissue plasminogen activator (tPA), tissue plasminogen activator total antigen, active plasminogen activator inhibitor-1 (PAI-1), plasminogen activator inhibitor total antigen (PAI-1TA), plasminogen activator inhibitor-1 and tissue plasminogen activator complex (PAI-1/tPA). These were analyzed using ELISA. The number of hospitalizations and complications related to small bowel obstruction (SBO) were recorded at 2 y after surgery. RESULTS: A total of 95 patients (72%) had sufficient peritoneal drain fluid suitable for ELISA analysis. Of them, 46 patients (48%) were from the oral simvastatin group. Mean tPA and tPA total antigen concentrations in peritoneal fluid were similar between the two groups. Mean PAI-1 and PAI-1 TA concentrations in the statin and placebo group were also similar. Mean PAI-1/tPA complex concentration was similar between the two groups. The number of hospitalizations from SBOs were 5 and 4 in the statin and placebo groups respectively (P = 0.46). The overall mortality at 2-year post-surgery was similar between the two groups (P = 0.59). CONCLUSIONS: In this pilot study involving humans, oral simvastatin had no measured effect on the peritoneal fibrinolytic pathway in the first 24 h after colorectal surgery. Analysis of clinical outcomes also showed that oral simvastatin did not reduce hospitalizations for SBO in the 2 y after surgery. Further studies may be useful to evaluate whether fibrinolytic pathways beyond 24 h are altered after systemic administration of statins and to evaluate the use of higher doses of statins, perhaps used intraperitoneally rather than systemically.

Perioperative Simvastatin Therapy in Major Colorectal Surgery: A Prospective, Double-Blind Randomized Controlled Trial.

BACKGROUND: Statins have numerous potential benefits relevant to abdominal surgery, and their use has been associated with a reduction in the systemic inflammatory response syndrome, wound infection, and anastomotic leak after colorectal surgery. However, this clinical evidence is limited to retrospective studies. The aim of this study was to prospectively investigate whether perioperative statin therapy can decrease the incidence of complications after major colorectal surgery. STUDY DESIGN: A prospective, double-blind, parallel-group, randomized controlled trial was conducted at 3 tertiary hospitals in New Zealand, between October 2011 and August 2013. Adult patients undergoing elective colorectal resection for any indication or reversal of Hartmann's procedure were randomized with a 1:1 patient allocation ratio to receive either 40 mg oral simvastatin or placebo once daily for 3 to 7 days preoperatively until 14 days postoperatively. The primary outcome was the overall incidence of complications for 30 days postoperatively. Secondary outcomes included the systemic and peritoneal cytokine response (interleukin [IL]-1α, IL-1ß, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]α) on postoperative day 1. RESULTS: There were 132 patients included in the study (65 simvastatin, 67 placebo). There were no significant differences between the 2 groups at baseline with regard to patient, operation, and disease characteristics. There were no significant differences between the 2 groups in the incidence, grade, and type of postoperative complications (simvastatin: 44 [68%] vs placebo: 50 [75%], odds ratio 0.71 [95% CI 0.33 to 1.52], p = 0.444). Plasma concentrations of IL-6, IL-8, and TNFα, and peritoneal concentrations of IL-6 and IL-8, were significantly lower in the simvastatin group postoperatively. CONCLUSIONS: Perioperative simvastatin therapy in major colorectal surgery attenuates the early proinflammatory response to surgery, but there were no differences in postoperative complications.

Predictors of acute diverticulitis severity: A systematic review.

BACKGROUND: Diverticulitis is a common condition with a broad spectrum of disease severity. A scoring system has been proposed for diagnosing diverticulitis, and a number of scoring systems exist for predicting prognosis associated with severe complications of diverticulitis such as peritonitis. However, predicting disease severity has not received as much attention. Therefore, the aim of this review was to identify the factors that are predictive of severe acute diverticulitis. METHODS: A systematic literature search was performed using Medline, PubMed, EMBASE, and the Cochrane Library to identify papers that evaluated factors predictive of severe diverticulitis. Severe diverticulitis was defined as complicated diverticulitis (associated with haemorrhage, abscess, phlegmon, perforation, purulent/faecal peritonitis, stricture, fistula, or small-bowel obstruction) or diverticulitis that resulted in prolonged hospital admission, surgical intervention or death. RESULTS: Twenty one articles were included. Studies were categorised into those that identified patient characteristics (n = 12), medications (n = 5), biochemical markers (n = 8) or imaging (n = 3) as predictors. Predictors for severe diverticulitis included first episode of diverticulitis, co-morbidities (Charlson score ≥ 3), non-steroidal anti-inflammatory drug use, steroid use, a high CRP on admission and severe disease on radiological imaging. Age and gender were not associated with disease severity. CONCLUSION: A number of predictors exist for identifying severe diverticulitis, and CT remains the gold standard for diagnosing complicated disease. Patients who present with identified risk factors for severe disease warrant early imaging, closer in-patient observation and a lower threshold for early surgical intervention. Patients without these factors may be suitable for outpatient-based treatment.

Five-year results after laparoscopic sleeve gastrectomy: a prospective study.

BACKGROUND: Whilst the early to mid-term efficacy of laparoscopic sleeve gastrectomy (SG) is well established, there is comparatively less detailing of long-term efficacy. The objectives of this study were to evaluate the long-term outcomes of patients undergoing SG at the authors' institution. METHODS: All patients undergoing SG during the past 5 or more years were eligible. Outcomes included baseline demographic data, preoperative characteristics, percentage excess weight loss (%EWL), co-morbidity improvement and resolution, serum hemoglobin A(1c) (HbA(1c)), serum lipid profile, and the Bariatric Analysis Reporting Outcome System (BAROS) questionnaire. A subset analysis was also performed with patients stratified in to super obese (body mass index ≥ 50 kg/m(2)). RESULTS: There were 96 patients who underwent surgery between March 2007 and July 2008. Of these, 10 declined to participate, 28 were unable to be contacted, and 3 were deceased; therefore, 55 patients were included in the analysis. The mean yearly %EWL to postoperative year 5 was 56% (year 1), 55% (year 2), 46% (year 3), 43% (year 4), and 40% (year 5). Combined improvement and resolution rates at 5 years were 79%, 61%, and 73% for type 2 diabetes, hypertension, and obstructive sleep apnea, respectively. The HbA(1c) was significantly reduced at long-term follow-up. The mean BAROS score was 3.13 (95% CI: 2.4, 3.9). Weight loss outcomes were less favorable in super obese patients. CONCLUSION: Weight loss outcomes at 5 year follow-up were modest after SG though improvement in co-morbidity status was maintained.

Efficacy of general practitioners with specialty interests for surgical procedures.

BACKGROUND: General practitioners with specialty interests (GPwSIs) have been an emerging entity in the last decade or so and aim to improve patient's access to specialist level care in the primary care setting. This is achieved by them providing equivalent quality and outcomes to secondary consultant-led services, while not necessarily providing the same breadth of clinical care as them. In this systematic review, we attempt to address their efficacy for surgical procedures and specialties. METHODS: PRISMA guidelines were followed and an electronic literature search was performed independently by two authors using predefined search terms across EMBASE, Ovid MedLine, PubMed, PSYCINFO and the Cochrane Library databases. A total of 817 articles were reviewed after which only six were included for the systematic review. RESULTS: Of the six articles selected, three studies analysed efficacy of GPwSIs with regard to surgical excision of skin lesions. One study looked at the economic evaluation of a GPwSI-led dermatology service in primary care and included GPwSIs carrying out skin excisions. The remaining two included studies were from the same institution and evaluated hernia repairs at a single centre general practitioner practice. CONCLUSION: There is generally, a paucity of evidence looking at the efficacy of GPwSIs for surgical procedures. While they seem to provide an acceptable standard of specialist care in the primary care setting, they do not appear to save money. However, they provide an alternative workforce and the improved access to care that results from it may offset their higher costs.

Goal-directed fluid therapy in major elective rectal surgery.

INTRODUCTION: Goal-Directed Fluid Therapy (GDFT) has been previously shown to decrease complications and hospital length of stay in major colorectal surgery but the data are not specific to rectal surgery and may be potentially outdated. This study investigated whether GDFT provides clinical benefits in patients undergoing major elective rectal surgery. METHODS: There were 81 consecutive patients in this cohort study. Twenty-seven patients were allotted to GDFT using the Oesophageal Doppler Monitor (ODM) and received boluses of colloid fluid based on corrected flow time and stroke volume. These patients were compared with a historical cohort of the previous 54 patients managed without the ODM. The primary endpoint of the study was 30-day total complications which were defined and graded. Secondary endpoints included hospital length of stay (LOS) and fluid volumes administered. RESULTS: There were no differences at baseline between the two groups. Patients in the treatment group received a higher volume of colloid fluids (1000 mL vs. 500 mL; p < 0.01) but there were no differences in overall fluid volumes administered intraoperatively (3000 mL vs. 3000 mL; p = 0.41). A non-significant trend (p = 0.06) suggested that patients allotted to GDFT had decreased fluid requirement in the first 24 h after surgery. There were no differences in median total fluid volumes (12700 mL vs. 10407 mL; p = 0.95), total complications (22 [81%] vs. 44 [81%]; p = 1.00) or median hospital LOS (9 days vs. 10 days; p = 0.92) between the two groups. CONCLUSION: Intraoperative GDFT did not improve clinical outcomes following major elective rectal surgery.

The relationship between academic assessment and psychological distress among medical students: a systematic review.

A systematic review was conducted to determine the relationship between academic assessment and medical student psychological distress with the aim of informing assessment practices. A systematic literature search of six electronic databases (Medline, Medline IN PROCESS, PubMed, EMBASE, Psychinfo, ERIC) from 1991 to May 2014 was completed. Articles focusing on academic assessment and its relation to stress or anxiety of medical students were included. From 3,986 potential titles, 82 full-text articles were assessed for eligibility, and 23 studies met review inclusion criteria. Studies focused on assessment stress or anxiety, and assessment performance. Consistent among the studies was the finding that assessment invokes stress or anxiety, perhaps more so for female medical students. A relationship may exist between assessment stress or anxiety and impaired performance. Significant risks of bias were common in study methodologies. There is evidence to suggest academic assessment is associated with psychological distress among medical students. However, differences in the types of measures used by researchers limited our ability to draw conclusions about which methods of assessment invoke greater distress. More rigorous study designs and the use of standardized measures are required. Future research should consider differences in students' perceived significance of assessments, the psychological effects of constant exposure to assessment, and the role of assessment in preparing students for clinical practice.

Newly diagnosed diabetes mellitus after acute pancreatitis: a systematic review and meta-analysis.

BACKGROUND: Diabetes mellitus (DM) is common in the general population and it poses a heavy burden to society in the form of long-term disability, healthcare use and costs. The pancreas is a key player in glucose homeostasis, but the occurrence of newly diagnosed DM after acute pancreatitis (AP), the most frequent disease of the pancreas, has never been assessed systematically. The aim of this study was to conduct a systematic literature review to determine the prevalence and time course of DM and related conditions after the first attack of AP as well as the impact of covariates. METHODS: Relevant literature cited in three electronic databases (Scopus, EMBASE and MEDLINE) was reviewed independently by two authors. The main outcome measures studied were newly diagnosed prediabetes, DM, or DM treated with insulin. Pooled prevalence and 95% CIs were calculated for all outcomes. RESULTS: A total of 24 prospective clinical studies, involving 1102 patients with first episode of AP, met all the eligibility criteria. Prediabetes and/or DM was observed in 37% (95% CI 30% to 45%) individuals after AP. The pooled prevalence of prediabetes, DM and treatment with insulin after AP was 16% (95% CI 9% to 24%), 23% (95% CI 16% to 31%), and 15% (95% CI 9% to 21%), respectively. Newly diagnosed DM developed in 15% of individuals within 12 months after first episode of AP and the risk increased significantly at 5 years (relative risk 2.7 (95% CI 1.9 to 3.8)). A similar trend was observed with regard to treatment with insulin. The severity of AP, its aetiology, individuals' age and gender had minimal effect on the studied outcomes. CONCLUSIONS: Patients with AP often develop prediabetes and/or DM after discharge from hospital, and have a greater than twofold increased risk of DM over 5 years. Further studies are warranted to determine the optimal strategy for its detection and whether the risk of developing DM after AP can be reduced.

Interhospital transfer of acute general surgical patients in the Taranaki region of New Zealand.

AIM: This study investigated the transfer of acute general surgical patients from HPH to TBH in order to evaluate Interhospital transfer time in a rural New Zealand setting. It specifically investigates the prioritisation and time to transfer of unwell patients who required ICU/HDU admission following transfer. METHOD: 9 months case-control retrospective study based on review of ambulance' "patient transfer sheets" and patients' medical records. Ambulance transfers of General Surgical emergencies were divided into two groups and analysed with group 1 admitted to ICU (ICU group) versus those admitted to the wards (non-ICU group). RESULTS: The majority of patients in the non-ICU group (34 patients, 77%) were managed conservatively while 8 patients (18%) underwent operative intervention. Four patients (24%) in the ICU group had surgery while 7 patients (41%) needed specialist investigations such as gastroscopy (n=5), ERCP (n=1) or angiography (n=1). One patient in each group died during their admission at TBH. CONCLUSIONS: There was no statistically significant difference in ambulance transfer times between the ICU and non-ICU groups (138 versus 124 minutes respectively), with the main determinant being the "ambulance response time" which could have been shortened by better identification of acute general surgical patients who ultimately required ICU/HDU care following transfer. The development of local protocols and checklists ensuring necessary communication between hospital and ambulance staff may allow better triage and prioritisation of transfer and lead to shorter transfer times for more unwell patients.

Fast-track elective colectomy: single-surgeon experience of 100 consecutive cases.

AIMS: In 2005, the senior author (AGH) initiated an Enhanced Recovery After Surgery (ERAS) or 'fast-track' programme for elective colonic surgery at the Manukau Surgery Centre aimed at improving perioperative care. We reviewed the senior author's experience of elective colectomy conducted within the ERAS programme and evaluated clinical outcomes. METHODS: Using a prospectively maintained database, consecutive patients who underwent elective colonic resection by the senior author within the ERAS programme at the Manukau Surgery Centre between December 2005 and March 2012 were reviewed. Demographic and operative data were recorded and clinical outcomes including complications, hospital stay and readmissions were evaluated for 30 days postoperatively. RESULTS: 100 consecutive patients were reviewed. The median age of patients was 70 years (range: 16-92) and the most common indication for surgery was malignancy (81 cases). Right-sided colectomy was performed in 52 cases while 45 patients had a left-sided colectomy and 3 patients underwent subtotal colectomy. The median day to discharge was 3 days while total hospital stay was 4 days which incorporated 21 readmissions for mostly minor complications. Major complications occurred in only 8 patients and included 4 anastomotic leaks. CONCLUSION: In one surgeon's experience, elective colectomy performed within an optimised perioperative care environment achieves shorter hospital stay with a low rate of major complications.

Effect of preoperative exercise on cardiorespiratory function and recovery after surgery: a systematic review.

BACKGROUND: This systematic review aims to investigate the extent to which preoperative conditioning (PREHAB) improves physiologic function and whether it correlates with improved recovery after major surgery. METHODS: An electronic database search identified randomized controlled trials (RCTs) investigating the safety and efficacy of PREHAB. The outcomes studied were changes in cardiorespiratory physiologic function, clinical outcomes (including length of hospital stay and rates of postoperative complications), and measures of changes in functional capacity (physical and psychological). RESULTS: Eight low- to medium-quality RCTs were included in the final analysis. The patients were elderly (mean age >60 years), and the exercise programs were significantly varied. Adherence to PREHAB was low. Only one study found that PREHAB led to significant improvement in physiologic function correlating with improved clinical outcomes. CONCLUSION: There are only limited data to suggest that PREHAB confers any measured physiologic improvement with subsequent clinical benefit. Further data are required to investigate the efficacy and safety of PREHAB in younger patients and to identify interventions that may help improve adherence to PREHAB.

The Surgical Recovery Score correlates with the development of complications following elective colectomy.

BACKGROUND: The Surgical Recovery Score (SRS) is a validated, comprehensive recovery assessment tool used to measure functional recovery after major surgery. To further evaluate its clinical applicability, this study investigated whether the SRS correlates with clinical outcomes and the occurrence of complications after elective colectomy. MATERIALS AND METHODS: We conducted a retrospective review of prospectively collected data for consecutive patients undergoing elective colonic resection within an enhanced recovery program at our institution from September 2008 to September 2011. We administered the 31-item SRS questionnaire preoperatively (baseline) and on postoperative days 1, 3, 7, 14, and 30. We scored individual questionnaires as a percentage of the maximum possible score, with a higher SRS indicating improved functional recovery (range, 17-100). We prospectively recorded clinical outcomes and graded 30-d complications as per the Clavien-Dindo classification. We conducted univariate and logistic regression analysis to determine the correlation of the SRS to the development of complications. RESULTS: We evaluated 134 patients, 62 of whom developed minor complications (grades 1-2) (46%) and 21 of whom developed major complications (grades 3-5) (16%). The SRS was similar at baseline in the complicated and uncomplicated groups but significantly lower on postoperative days 3, 7, 14, and 30 in patients who developed major complications, and on days 7 and 14 in patients who developed minor complications. In a logistic regression analysis, the SRS on postoperative day 3 was independently associated with the development of any complication, as well as major complications specifically. CONCLUSIONS: In addition to measuring functional recovery, the SRS closely correlates with the development of complications after elective colectomy and offers a reliable outcome measure to assess overall postoperative recovery.

Optimizing perioperative care in bariatric surgery patients.

Enhanced recovery after surgery (ERAS) programs have been shown to minimise morbidity in other types of surgery, but comparatively less data exist investigating ERAS in bariatric surgery. This article reviews the existing literature to identify interventions which may be included in an ERAS program for bariatric surgery. A narrative literature review was conducted. Search terms included 'bariatric surgery', 'weight loss surgery', 'gastric bypass', 'ERAS', 'enhanced recovery', 'enhanced recovery after surgery', 'fast-track surgery', 'perioperative care', 'postoperative care', 'intraoperative care' and 'preoperative care'. Interventions recovered by the database search, as well as interventions garnered from clinical experience in ERAS, were used as individual search terms. A large volume of evidence exists detailing the role of multiple interventions in perioperative care. However, efficacy and safety for a proportion of these interventions for ERAS in bariatric surgery remain unclear. This review concludes that there is potential to implement ERAS programs in bariatric surgery.

Single-stage laparoscopic sleeve gastrectomy: safety and efficacy in the super-obese.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is increasingly used as a single-stage bariatric procedure. However, its safety and efficacy in super-obese patients (body mass index [BMI] > 50 kg/m(2)) is less well defined. This series reports on 400 consecutive patients who underwent LSG at our institution, to evaluate safety and efficacy in the super-obese. MATERIALS AND METHODS: We performed a retrospective review of prospectively collected data on 400 consecutive patients who underwent LSG at our institution. We analyzed baseline demographic data, median length of hospital stay, complications, length of follow-up, weight loss, and comorbidity resolution. We graded complications according to the Clavien-Dindo classification system. We classified patients as super-obese and non-super-obese and compared outcomes between groups. We used the two-tailed t-test and Fisher's exact test as necessary. RESULTS: There were 400 patients, 291 of whom were female (73%). The mean age was 44 y (standard deviation [SD] ± 9 y). The mean preoperative weight and BMI were 140 kg (SD ± 31 kg) and 49 kg/m(2) (SD ± 9 kg/m(2)), respectively. There were 67 complications (16%) in total. The major complication rate was 7.2%, with one recorded death. The median length of hospital stay was 3 d, and the mean follow-up period was 1 y. A total of 170 patients (43%) were super-obese, with a mean preoperative BMI of 56 kg/m(2) (SD ± 5 kg/m(2)). The mean absolute weight loss (59 versus 36.7 kg; P < 0.01) and percentage excess weight loss (58.9% versus 45.9%; P < 0.01) was significantly higher in the super-obese. The mean postoperative BMI for super-obese patients was 38.9 kg/m(2). There was no difference between groups in the incidence of major complications (8.2% versus 6.5%; P = 0.56). CONCLUSION: Laparoscopic sleeve gastrectomy is safe and effective in the super-obese, with acceptable weight loss and no increase in the major complication rate.

Perioperative use of statins in elective colectomy.

BACKGROUND: Statins have many beneficial effects and may attenuate the proinflammatory and metabolic stress response to surgery and consequently reduce postoperative morbidity. OBJECTIVE: This study investigated whether perioperative use of statins improved short-term outcomes after elective colectomy. DESIGN: This study is a retrospective review of prospectively collected data. SETTINGS AND PATIENTS: This study was conducted in consecutive patients undergoing elective colonic resection within an enhanced recovery program at a tertiary hospital (Manukau Surgery Centre, Middlemore Hospital, Auckland, New Zealand) from January 2005 to December 2010. MAIN OUTCOME MEASURES: Complications, hospital stay, and readmissions were recorded for 30 days postoperatively. Postoperative functional recovery was measured by the use of the validated Surgical Recovery Score. Serum proinflammatory cytokines were measured on postoperative day 1. RESULTS: There were 269 patients; 86 patients were on a statin perioperatively, whereas 183 patients had no statin. Members of the statin group were older (median age, 72 vs 69 years; p = 0.021), included more men (53% vs 40%; p = 0.049), and included a higher number of patients with an ASA score of 3 (55% vs 22%; p < 0.001). Patients on statin therapy had a significantly lower number of anastomotic leaks (1% vs 7%; p = 0.031). However, there was no significant difference in total complications or median hospital stay. The 2 groups had comparable functional recovery, and there was no significant difference in serum cytokine levels. LIMITATIONS: This retrospective study did not analyze type, duration, or dose of statins given perioperatively. CONCLUSION: Patients on perioperative statins had greater baseline perioperative risks compared with nonusers, but they achieved equivalent outcomes overall. Statin use was associated with reduced anastomotic leaks. Thus, perioperative statin use may reduce morbidity after elective colectomy, and this finding warrants further investigation.

Medical students-as-teachers: a systematic review of peer-assisted teaching during medical school.

INTRODUCTION: International interest in peer-teaching and peer-assisted learning (PAL) during undergraduate medical programs has grown in recent years, reflected both in literature and in practice. There, remains however, a distinct lack of objective clarity and consensus on the true effectiveness of peer-teaching and its short- and long-term impacts on learning outcomes and clinical practice. OBJECTIVE: To summarize and critically appraise evidence presented on peer-teaching effectiveness and its impact on objective learning outcomes of medical students. METHOD: A literature search was conducted in four electronic databases. Titles and abstracts were screened and selection was based on strict eligibility criteria after examining full-texts. Two reviewers used a standard review and analysis framework to independently extract data from each study. Discrepancies in opinions were resolved by discussion in consultation with other reviewers. Adapted models of "Kirkpatrick's Levels of Learning" were used to grade the impact size of study outcomes. RESULTS: From 127 potential titles, 41 were obtained as full-texts, and 19 selected after close examination and group deliberation. Fifteen studies focused on student-learner outcomes and four on student-teacher learning outcomes. Ten studies utilized randomized allocation and the majority of study participants were self-selected volunteers. Written examinations and observed clinical evaluations were common study outcome assessments. Eleven studies provided student-teachers with formal teacher training. Overall, results suggest that peer-teaching, in highly selective contexts, achieves short-term learner outcomes that are comparable with those produced by faculty-based teaching. Furthermore, peer-teaching has beneficial effects on student-teacher learning outcomes. CONCLUSIONS: Peer-teaching in undergraduate medical programs is comparable to conventional teaching when utilized in selected contexts. There is evidence to suggest that participating student-teachers benefit academically and professionally. Long-term effects of peer-teaching during medical school remain poorly understood and future research should aim to address this.

Intestinal differentiation in zebrafish requires Cdx1b, a functional equivalent of mammalian Cdx2.

BACKGROUND & AIMS: The ParaHox transcription factor Cdx2 is an essential determinant of intestinal phenotype in mammals throughout development, influencing gut function, homeostasis, and epithelial barrier integrity. Cdx2 expression demarcates the zones of intestinal stem cell proliferation in the adult gut, with deregulated expression implicated in intestinal metaplasia and cancer. However, in vivo analysis of these prospective roles has been limited because inactivation of Cdx2 in mice leads to preimplantation embryonic lethality. We used the zebrafish, a valuable model for studying gut development, to generate a system to further understanding of the role of Cdx2 in normal intestinal function and in disease states. METHODS: We isolated and characterized the zebrafish cdx1b ortholog and analyzed its function by antisense morpholino gene knockdown. RESULTS: We showed that zebrafish Cdx1b replaces the role of Cdx2 in gut development. Evolutionary studies have indicated that the zebrafish cdx2 loci were lost following the genome-wide duplication event that occurred in teleosts. Zebrafish Cdx1b is expressed exclusively in the developing intestine during late embryogenesis and regulates intestinal cell proliferation and terminal differentiation. CONCLUSIONS: This work established an in vivo system to explore further the activity of Cdx2 in the gut and its impact on processes such as inflammation and cancer.